[Chazz8]

Plastic does not melt for no reason parked in the shade … Unless it is made (super) wrong. So I don’t expect Toyota mechanics to say the plastic is made wrong (unless it’s obvious) and shift to more likely reasons, like solar convergence or vandalism. That is how Toyota Dealership personnel will think and act. I suggest getting more information and try to reproduce the melting (more melting?)

This is the same trim area that others Rav4 owners have had melting issues so it does make me think that it’s possible that Toyota used the wrong plastic formula or had a bad batch?

Search locally for news of solar convergence to see if you have a building you park nearby has a reputation for melting cars or others have reported (local) melting vandalism. Put a camera on the parked vehicle to catch melting in the act and determine reason.

Start an experiment to see how Toyota trim plastic holds up relative to other manufacturers under increasing heat.

Let’s see if anybody has started the investigation and chimes in.

Edit; I’m going to look for ways that sun can reflect of your own vehicle to melt those areas. When you have posted enough (10 post?) you can add pictures to your post to show me where on the side mirror it melted.